1. Field of the Invention
This invention relates to instruments for microwave power monitoring and more particularly, to a portable unit responsive to the power density of a microwave field.
The expanding use of high frequency, or microwave equipment, has brought with it a realization that improper or excess exposure to microwaves, may be injurious. Recognition of this fact has given rise to Government regulations and equipment must be carefully designed to avoid potentially harmful leakage.
Since such electromagnetic radiation is invisible and the human body does not physically "sense" the presence of microwave impingement, it is necessary to use electronic instruments for purposes of detection and measurement. There is a widening need for reliable and economical monitoring instruments that can be properly used, even by inexperienced operators.
2. Description of the Prior Art
Measuring instruments for microwave power have emmerged from earlier devices placed within wave guides, to sophisticated units and components which measure power density when worn or held within the general area of a suspected source of radiation. The inventor's U.S. Pat. No. 3,641,439, which issued Feb. 8, 1972, discloses a pioneer probe for sensitively detecting microwave radiation with a minimum of field perturbation. More economical units have also been developed, with the sacrifice of sensitivity and linearity of measurement. U.S. Pat. No. 4,032,910, for example, discloses a unit utilizing a diode detector and an alarm operative when the energy of an incident microwave field is above a predetermined level. To date, neither the latter unit, nor others, furnish the necessary reliability or sensitivity for compliance with Governmental regulations and recognized health safety standards.